Name:GitHub Pull Request from Unknown User id:9d7b9100-8878-4404-914e-ca5e551a641e version:3 date:2024-09-30 author:Patrick Bareiss, Splunk status:production type:Anomaly Description:The following analytic detects pull requests from unknown users on GitHub. It uses a Splunk query to identify pull requests where the user ID is not specified and cross-references these with a known users lookup table. This activity is significant because pull requests from unknown users can introduce malicious code or unauthorized changes to repositories. If confirmed malicious, this could lead to unauthorized code changes, data breaches, or other security incidents. Immediate steps include reviewing the author's name, repository, head reference, and commit message, and investigating any related artifacts and processes. Data_source:
-GitHub
search:`github` check_suite.pull_requests{}.id=* | stats count by check_suite.head_commit.author.name repository.full_name check_suite.pull_requests{}.head.ref check_suite.head_commit.message | rename check_suite.head_commit.author.name as user repository.full_name as repository check_suite.pull_requests{}.head.ref as ref_head check_suite.head_commit.message as commit_message | search NOT `github_known_users` | eval phase="code" | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `github_pull_request_from_unknown_user_filter`
how_to_implement:You must index GitHub logs. You can follow the url in reference to onboard GitHub logs. known_false_positives:unknown References: -https://www.splunk.com/en_us/blog/tips-and-tricks/getting-github-data-with-webhooks.html drilldown_searches: name:'View the detection results for - "$repository$"' search:'%original_detection_search% | search repository = "$repository$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$repository$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$repository$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Dev Sec Ops' asset_type:GitHub confidence:90 impact:30 message:Vulnerabilities found in packages used by GitHub repository $repository$ mitre_attack_id: - 'T1195.001' - 'T1195' observable: name:'repository' type:'Other' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'alert.id' - 'repository.full_name' - 'repository.html_url' - 'action' - 'alert.affected_package_name' - 'alert.affected_range' - 'alert.created_at' - 'alert.external_identifier' - 'alert.external_reference' - 'alert.fixed_in' - 'alert.severity' risk_score:27 security_domain:network
